Mechanical vibrator



March 27, 1962 c. F. CARLSON 3,026,733

MECHANICAL VIBRATOR Filed Oct. 2, 1958 ,Ziz (Jen/56v gZare/zz C6 FUaFZSmite States Patent 3,026,733 MEQHANICAL VHBRATOR Clarence F. (Iarlson,751 Spring St, Aurora, Ill. Filed Get. 2, 1953, fier. No. 764-352 4illaims. (Cl. 74-87) This application is filed as a continuation-in-partof my copending application, Serial No. 699,236, filed November 27,1957, and now abandoned, the disclosure of which is hereby specificallyincorporated by reference,

This invention relates to a mechanical vibrator where in a vibratilehollow body receives a rotatably mounted drive shaft for one or moremass elements such as ball or roller type bearings which are confinedloose within said body for movement about the axis of the shaft inunbalanced distribution thereabout.

Such vibrators are useful in a Wide variety of applications; forexample, they may be arranged for contact with freshly poured concreteto assist in the operation of puddling the concrete; or they may beembodied as the vibration source for a massaging device; or they may bearranged to vibrate a screen-like member such as is used in the gradingor sorting of sand, gravel, or coal. Applications for such vibrators arequite numerous, and the above examples are not intended as limitationsto the field of use of the invention.

The present invention is particularly concerned with vibrators of theclass that utilizes a direct mechanical drive between the source ofpower and the vibrator itself, as distinguished from the class ofvibrators wherein the vibrator is actuated directly by pneumatic power.in the case of the direct mechanical-drive type vibrators of the priorart, the bearings for the rotatable drive shaft are subjected to intensewear, which greatly limits their useful life.

It is the principal object of the present invention to provide avibrator arrangement that is capable of withstanding intense usage overextended periods of time without failure or impairment; that may beoriented to any desired position of use; that allows for readyadjustment of the frequency and amplitude of the vibrations produced;that is substantially free of frictional drag in the driving system; andthat eliminates the need of close manufacturing tolerances and hence iseasier and more economical to construct.

Another object is to provide a vibrator of the above type wherein thevibration-producing mass is arranged loose within a vibratile barrel.

It is a further and specific object of this invention to provide avibrator of the above-mentioned type with a direct mechanical drive.

Other objects and advantages will become apparent during the course ofthe following description.

In the accompanying drawings forming a part of this specification and inwhich like numerals are employed to designate like parts throughout thesame:

FIG. 1 is a longitudinal sectional view disclosing the vibrator of thisinvention;

FIG. 2 is a side-sectional view taken along the line 2-2 of (FIG. 1; and

FIGS. 3 and 4 are side-sectional views generally corresponding to theview of FIG. 2 and illustrating two further embodiments of a vibratorconstructed in accordance with the present invention.

Referring now to the drawings, the invention is dis closed in the formof a mechanical-drive type vibrator wherein the motion of a rotatableshaft is translated into vibrations of a vibratile hollow body member 11through the medium of a mass 25 disposed loosely within the hollowmember.

The driving power for the shaft of the disclosed ar- 3,fi2fi,733Patented Mar. 27, 1952 rangement may either be supplied from an electricmotor or pneumatic motor or any other suitable source of rotary power,and the connection between the driving motor and the driven shaft mayeither be in the form of a rigid extension of the drive shaft or in theform of a flexible coupling shaft.

In applications such as involved in the puddling of concrete wherein thevibrator is in actual contact with the concrete, an outer protectiveshell may be applied over the vibratile member. If, in such anarrangement, the shaft includes a rigid extension to a driving motor,the protective shell may be extended to encase both the vibrator and themotor. Where a screen-like member such as is used in grading or sortingis to be vibrated, the vibrator may be directly secured thereto, inwhich case a protective shell may not be required.

The various arrangements for adapting the vibrato of the presentinvention to the wide variety of potential uses which exist for it willbe apparent to those skilled in this art, and the present invention isbasically concerned with the construction of the vibrator itself.

In the vibrator construction illustrated in FIGS. 1 and 2 for purposesof disclosure, the drive shaft 10 carries a plurality of fins 13 spacedat equal intervals thereabout to provide a dynamically balanced shaft.The vibratile member 11 is in the form of a cylinder or barrel thatdefines a lengthwise extending chamber and that is formed at itsopposite ends with annular recesses to present oppositely, outwardlyfacing, annular abutment shoulders 113; the mass 25 is in the form of aroller type bearing for minimizing internal friction and is confinedbetween the barrel 11 and the shaft 10 in unbalanced distribution aboutthe axis of rotation of the shaft and disposed throughout the length ofthe chamber defined thereby. Preferably the fins 13 extend to a pointclosely adjacent the cylindrical internal surface defined by the barrelill to form the chamber into a plurality of cOrnpartments 14- thatextend the length of the chamber, with the ends of such compartmentsbeing sealed by end plates 15 insertable in the recesses at the ends ofthe barrel for abutting engagement with the annular shoulders MS. Theend plates are secured in their illustrated position by snap rings, asindicated at 16, or in any other desired manner. The end plates areformed with aligned openings 17 through which the ends of the shaft 10extend, and these plates are preferably arranged to provide annularpockets flanking the openings 17 for receiving anti-friction facilitieswhich, as shown at 18, may be in the form of ball-bearing assemblies.The ball-bearing assemblies 18 are isolated from the cylindrical pocketdefined by the annular wall portions 19 that flank the openings 17, andthey may be held in place by a snap-ring arrangement 2% or in any othersuitable manner.

Therefore, the shaft 10 is supported at its opposite ends in theball-bearing assemblies 18, and it is in perfect dynamic balance sothat, upon rotation thereof, no appreciable eccentric loading of theball-bearing assemblies occurs. The bearings for the shaft, therefore,will have a long, effective life.

The vibrations of the vibratile barrel 11 are produced by the action ofthe mass 25, which is driven circumferentially about the axis of theshaft by the rotating fins 13. The frequency of the vibrations producedin the barrel 11 is primarily dependent upon the speed of rotation ofthe shaft 10, while the magnitude of the vibrations is dependent uponthe weight and distribution arrangement of the mass within the barrel.

One of the important features of the invention resides in the fact thatthe mass, the motion of which sets up the vibrations in the barrel,derives its momentum from the drive shaft 10, but since it is loose withrespect to the drive shaft, imparts no eccentric loading upon the shaft,and, hence, no eccentric loading upon the shaft bearings 18. These shaftbearings have been the usual point of failure in prior art vibratorsemploying a mechanical drive.

While three fins 13 are shown in the arrangement of FIGS. 1 and 2, itshould be apparent that any number of fins may be employed, though ineach case it is desirable to provide for dynamic balancing of the shaft.

Another feature of the vibrator construction resides in its economy ofmanufacture. The clearance between the fins 13 and the cylindricalinternal surface of the barrel 11 is not critical; and it is, in fact,desirable that these parts do not engage in any manner in order, again,to minimize internal friction.

For purposes of reducing internal friction, a suitable lubricant isprovided in the barrel 11. Preferably the shaft is provided with an oilpassage 22 opening through the free end thereof to permit introducingoil after the vibrator is completely assembled. A suitable threaded plug23 seals the passage 22, the inlet of which is suitably tapped for thispurpose.

It will be apparent that the distinctive characteristic of theembodiment of FIGS. 1 and 2 resides in the use of an elongated roller 25as the mass element. This roller preferably extends substantially theentire length of the barrel chamber with sufficient end clearances beingprovided for free movement of the roller within the chamber.

It should be understood that one or more rollers suitably distributed inseparate compartments may be provided as required, and the rollers maybe of a variety of sizes in accordance with the particular vibrationcharacteristic required. The use of elongated rollers has the advantageover the use of ball bearings that the tremendous pressure on the barrelwall is more uniformly distributed along the length of the wall, andthis minimizes wear and scoring of the barrel wall.

While roller bearings of uniform cylindrical surface configuration arecontemplated within the scope of this invention, the roller elementdisclosed in the embodiment of FIGS. 1 and 2 is shown formed with ahelical screwlike groove 26 to provide a smooth-surfaced, screw-likeroller element that exhibits superior performance characteristics interms of low internal friction resulting from a superior lubricatingaction and in terms of reduced heat and wear resulting from a moreuniform distribution of pressure along the length of the barrel wall. Asis apparent in FIG. 1, any longitudinal cross section through the rolleris characterized by alternate lands and grooves.

The improved results are attained principally because of the activelubricating action that is developed with the grooved screw-like rollerbearing element, the grooves of which continuously and uniformly spreadthe lubricant on the surface of the barrel wall, as distinguished from auniform cylindrical roller element which continuously acts to push thelubricant ahead of it. Tests indicate that with the screw-type roller,the internal surface of the barrel wall is actually subjected to aburnishing action rather than a Wearing action.

There are a number of forms which the roller bearing element may take,depending upon the vibration requirement of the various applicationsthat may be made of the vibrator of this invention. As shown in FIG. 3,the roller element 25' may be formed with an off-center bore- 25B toproduce an eccentric or pulsating vibration component. Alternatively, asshown in FIG. 4, one roller bearing element may be arranged withinanother, in which case the outer roller bearing is in the form of acylindrical tube 27 and the other roller bearing 28 rides within thetube-like element 27 and acts to develop its own vibrationalcharacteristic that is superimposed upon the vibrational characteristicproduced by this tube alone. In any of these arrangements the rollerbearings may be of a uniform surface configuration though, as explainedpreviously, they preferably are grooved to provide screwlike,fiat-surfaced roller elements. In the FIG. 4 arrangement where onebearing operates within another, the inner bearing may have an eccentriclengthwise bore to provide still an additional vibration component.

It should be understood that the description of the preferred form ofthe invention is for the purpose of complying with Section 112, Title35, of the US. Code, and that the claims should be construed as broadlyas prior art will permit.

I claim:

1. In a rotatively operated vibration device adapted for attachment to amember to be vibrated, a vibratile hollow body defining a lengthwiseextending chamber, lubricant in said chamber, a rotatably mounted shaftextended lengthwise through said body axially of said chamber, and agenerally cylindrical roller bearing element confined loose within saidchamber to extend substantially the length thereof, said roller bearingelement having an eccentric bore extending lengthwise therethrough, withthe portion of said shaft within said body being of noncircular crosssection for driving said element about the axis of rotation of saidshaft by loose fitting abutting contact therewith.

2. The arrangement of claim 1 wherein a second roller bearing element isloose within and extends lengthwise through the bore in the first namedroller bearing element.

3. In a rotatively operated vibration device adapted for attachment to amember to be vibrated, a vibratile hollow body member having an internalsurface defining a lengthwise extending, generally cylindrical chamber,lubricant in said chamber, a rotatably mounted shaft extendinglengthwise through said member axially of said chamber, and a firstroller bearing member confined loose within said chamber to extendsubstantially the length thereof and having a generally cylindricalexternal surface, said roller bearing member having a bore extendinglengthwise therethrough and having a second roller bearing member loosewithin and extending lengthwise through said bore in said first rollerbearing element, with the portion of said shaft within said body memberbeing of non-circular cross section for driving said first rollerbearing member about the axis of rotation of said shaft by loose fittingabutting contact therewith such that said first roller bearing membermoves along the periphery of said chamber, with the external surface ofsaid first roller bearing member moving in rolling engagement with theinternal surface of said body member, one of said surfaces having alongitudinal cross-sectional surface configuration characterized byalternate lands and grooves facilitating continuous uniform spreading oflubricant on both of said surfaces by the rolling action therebetween.

4. In a rotatively operated vibration device adapted for attachment to amember to be vibrated, a vibratile hollow body having a cylindricalinternal surface surrounding and defining a lengthwise extendingcylindrical chamber, lubricant in said chamber, a rotatively mountedshaft extending lengthwise through said body axially of said chamber,and a first roller bearing element having a continuous helical groove inits external surface confined loose within said chamber and extendinglengthwise therein, said roller bearing element having a bore extendinglengthwise therethrough and having a second roller hearing element loosewithin and extending lengthwise through said bore in said first rollerbearing element, said second roller bearing element having a continuoushelical groove in its external surface, with the portion of said shaftwithin said body being of non-circular cross section for driving saidfirst roller bearing element about the axis of rotation of said shaft byloose fitting abutting contact therewith such that said first rollerbearing element moves along the periphery of said chamber with theexternal surface of said element in rolling engagement with the internalsurface of said body and exerting a continuous uniform spreading actionon lubricant between said surfaces.

(References on following page) References Cfified in the file of thispatent UNITED STATES PATENTS 512,438 1,459,841 Mitchell June 26, 1923igg z 2,422,639 Wenander June 17, 1947 3 2 2,479,799 Wilde Aug. 23, 19495 1 67 2,785,577 Nordegren Mar. 19, 1957 6 FOREIGN PATENTS Belgium July15, 1952 France June 17, 1953 France Sept. 8, 1954 France June 8, 1955(Addition to No. 1,063,465)

